Valve for rock drills



Jan. 20, 1931. .J-.' c. CURTIS 1,789,698

VALVE FOR ROCK DRILLS FiledJah. 16. 1930 VENTO ziolm a cuf zis. R

HIS ATTORNEY or shock which usually takes place in ma Patented Jan. 20,1931 "-UNITEDSTATES PATENT 'oFF1cE7- I]*- JOHNY'CPCURTIS, or msron,PENNSYLVANIA, nssranon 'ro xnennsonnnann an rm, or JERSEY an NEW EBSE Aconromwronor NEW JERSEY I VALVE on nocx nmnns Application medJ'anuaryi'lB, 1930; seriarne. 421,164.

This invention relates to rock drills, but more particularly to adistributing valve for rockdrills of the fluid actuated type.-

The objects of the invention are to obtain a quick and positive actionof the valve, to

assure a heavy blowof the hammer piston against the working implement,and to con- 1 trol the supply of pressure fluid to the ends of thepiston chamber in such manner that the hammer piston will strike heavilyagainst the working implement on its forward stroke and that the hammerpiston is actuated rearwardly without causing theobjectionable jarchines of this character. w 4

Other objects willbe in part'obvious and in partpointed outhereinafter:A

In the accompanying drawings forming part of thisspecification and inwhich similar reference characters refer to similar p v Figure 1 is asectional elevation of a-rock drillequipped with a valve constructed inaccordance with the practice of the invention, thevalve being showniii-position to supply pressure fluid to the rearward end of the pistonchamber, and V Figure 2 is v a similar view "showing the valve in aposition to supply pressure fluid to the front end of the pistonchamber.Referring more particularly, to the drawingsA designates generallyarockd'rill comprising a cylinder B wherein is formed 'a piston chamberC to accommodate a reciprocatory hammer piston D. In the wall of thecylinder B is a piston controlled exhaust port E to afford communicationbetween the piston chamber C and the atmosphere.

A suitable closure is provided for the front end of the piston chamber Cin the'form of a head F which may also act as a guide for a workingimplement G shown as extending withits rearward end into the pistonchamberto receive the blows ofthe hammer pistonD. I

A closure is provided for the rearward end of the piston chamberin theform ofa plate H whereon is seated a head block J which in turn servesas a seat for a back head The cylindervB, t ehead F and the elements dignated by H, J and K form the casing m of the rock drill and such partsmay be held in assembled relationship in anysuitablef'and conven ent*nianner, as for instance, usual side bolts (not shown). I

vention the head'block'J is provided witha bore=L toreceive a valvechest 0 having a e The valve s m be provided with e recess or cavlty Uto reduce its weight; 'Ne'arithe 7 forward end of the valve is anintegralflange Vwhich lies in the enlarged portion Q and spaced slightly'rearwardly of the'fl'ange is another flange W'which alsolieswithinyt'he enlarged portion Q.

by the V In accordance with the practiceof thein- The pressure flidintended to be die} tributedby the'valve is'introduced between 1 theflanges V and 'W by a port orports'X municate with a supply conduit Ythrough an annular passage Zin the head block J." if

The pressure fluid utilized for impelling thepiston D forwardly isadmitted into the in the valve chest O and the ports -X comrearward endof the piston chamber C through a rear inletpassageb in the plate I andcoaxially with the valve S, Thepressure fluid utilized for driving thepistonD rearwardly is conveyed to-thelfront end of the piston chamber bya front inlet passage 0 which extends through the cylinder B, the plateH and the head block J and'communicates with the rearward end of theenlarged.

portion Q, of the valve chamber through ports d in the valve chest 0.

In the flange V are a series of ports 6 through which the pressure fluidflows to the rear inletjpassage b andthe pressure fluid supplied to thefront inlet passage 10 flows through, ports f in theflange Theports eare preferably of greater area than vthe ports so that a greater amountofpressure fluid maybe supplied to the rearward end Of: the piston:chamber within a ,given time than to the front end. -This is desirablefor the reason that the forward stroke of the piston is the workingstroke. Convenient means are provided for actuating the valve S from onelimiting position to the-other. To tlllSBDCl the flange'V is provided atits forward end withan annularpressure area 9 against which the pressurefluid flowingthrough the ports a may, act to'throw the valve rearwardly.Similarly a pressure area h is formed on'the rearward'end of the flangeW so that pressure fluid flowing through the ports f will actthereagainst to throw the valve to its forward limiting position. p

Additional means are, however; provided to assist the pressurefluid'acting against the pressure areas 9 andh in throwingtheiyalve. Thevalve is accordingly provided with an 6 actuating surface 7' againstwliichwomp'ression from the rearward iendvofthe'= piston chamber mayact'to assist:thexpres'surefluid.

to the rear end of the piston-chamber-C to assist the. forcesactingagainst' the a ctuating surface 72 and the pressure surface'htomove the valveS forwardly. Thepressure fluid is, suppliedto theactuating surface owby a port 39 in the end wall'Q of the valvewS.

. In order to assure an immediate:- drop in the pressure fluid actingagainst the actuating surface 0 after the valve S has been movedforwardly, the valve chamber P: isproVijded with an exhaust passage 1which "leads through the valve chest 0 and the head block to theatmosphere and is controllediby the rear end of the stem: T.TheeX-ha-ust passage r is preferably so locatedthat it will be onlyuncovered bythe-stem T of the-valve when the valve reaches itsforemost'position in the valve chamber P.

The operation ofthe device is as follows: With the valve in the rearmostposition illustratedin Figure 1 pressure fluid will flow through theports 6 intoan'd through the front end of the valve chamber Pjthencethroughthe rearinlet passage Z; into the back end of the'piston chamberto drivethe piston D forwardly. V V

During the admission of pressure 'fl'uid into this end of the'pistonchamber pressure fluid will also pass through the port 19 in the endwall g of the val'veto act against the'actuating surface 0. "At'the'same time pressure fluid will be acting against the pres sure surfaces hand g and against the actuating surface y'.

Inasmuch that the actuating surface will be exposed to atmosphericpressure through -the inletipassagecythe pistoncham- I ber C and 'theexhaust port Eythe areas eX- posed. to pressure fluid for holdingthe'valve rearwardly will be somewhat in excessof those 'exposed 'topressure fluid tending to throw the'valve" inthe oppositedirection.

Thepiston D will then continue forwardly and at'the" instant the rearend of the piston D .startswto.uncovervtheiexhaust port E there will bea decided drop in pressure against the pressure Earea g andtheactuating, surface jsoi'thatthe pressures "acting against the pres? vsure areahand: the actuating surface 0 will immediately :start *the.valve forwardly. After'it-he valve starts in-this direction ,theactuating, surface 70 will also be -.exposed" to pressure fluid so thatthe valvewill be quickly moved I forwardly where 1 it will be held bythe-pressure acting againstthe pressure area h and'the actuatingsurfacek. I 1

JASIhB valve Sapproaches itsforemost sition-inthevalve chamber P.theexhaust passage riwillbe uncovered by the stemT ofthe valve and thepressure'fluid which previously acted againstthe actuating surface "96 0will then be exhausted to the-atmosphere.

This forward movement Qof .the 'valve v will take;place.at aboutthetimetthe piston delivers *it'sf blowf'to the working I implement. In thenew position of, the valve pressure fluid will flow through the ports f,the'ports (Land the front inlet passage '0 to thefront end of:the-piston'chamber O to actuate the piston-.Drrearwardly.

After the. exhaust portlEis coveredby the exhaust port E; The valve willthen be -held in "its: rearrnostposition by'the pressuresacting-"aaainst the entire front area of the r valve as well as againstthe actuating surface j. rI lclaimz' 1. In-a fluid-actuated rock drill,the combination of a 'cylinderhavinga piston chamber and a piston in thepiston chamberganbxha-ust port in the cylinden avalve c-hest haw ingi avalve chamber, inlet passages-leading fromtheends of the valve chamberto the pistoncha'mber, a valve in thevalve-chambercon? trolling theinlet passages and having a pairof flanges, a supply passage in thevalvechestfor supplying pressure fluid to the valve chamber between theflanges, pressure areas" on the flanges, ports in the flanges 1:01supplypressure fluid to the pressure areas-and to the'inlet passages,and opposed actuating surfaces on the valve, one of said actuatingsurfaces being intermittently exposed to pressure fluid to assist thepressure fluid acting against one pressure area to throw the valve inone di- V rection and the other actuating surface being intermittentlyexposed to compression to assist the pressure fluid acting against theother pressure area to return the valve.

2. In a fluid actuated rock drill, the combination of a cylinder havinga piston chamber and a piston in the piston chamber, an exhaust port inthe cylinder, a valve chest having a valve chamber, inlet passagesleading from the'ends' of the valve chamber to the piston chamber, avalve in the valve chamber having a pair of flanges, annular pressureareas on the flanges, ports in the flanges to supply pressure fluid tothe pressure areas for throwing the valve and to supply pressure fluidto the inlet passages, a supply passage in the valve chest to introducepressure fluid into the valve chamber between the flanges, a hollow stemon the valve and having an end wall to form opposed actuating surfaces,one of said actuating surfaces beingintermittently exposed tocompression to assist in I throwing the valve in one direction, and aport in the end wall supplying pressure fluid to the other actuatingsurface to assist in throwing the valve in the opposite direction.

3. In a fluid actuated rock drill, the combination of a cylinder havingapiston chamber and a piston in the piston chamber, an

exhaust port in the cylinder, a valve chest having a valve chamber,inlet passages leading from the ends of the Valve chamber tothe pistonchamber, a valve in the valve chamber having a pair of flanges, annularpressure areas on the flanges, ports in the flanges to supply pressurefluid to the pressure areas for throwing the valve and to supplypressure fluid to the inlet passages. a supply passage in the valvechest to introduce pressure fluid into the valve chamber betweentheflanges,

a hollow stem on the valve and having an end wall to form opposedactuating surfaces, one

of said actuating surfaces being intermittently exposed to compressionto assist in throwing the valve in one direction, a port in the end wallto supply pressure fluid from the rear end of the piston chamber to theother actuating surface to assist in throwing the valve in the otherdirection, and an exhaust port leading from the valve chamber to theatmosphere and controlled by'the stem to exhaust the fluid actingagainst the last said actuating surface.

In testimony. whereof I have signed this specification.

JOHN C. CURTIS.

